With the inauguration of Donald Trump this year, we have now had, for the first time in our history, three American presidents who were born in the same year. There have been three pairs of presidents born in the same year -- the very dissimilar John Quincy Adams and Andrew Jackson, in 1767; Richard Nixon and his surprise successor, Gerald Ford, in 1913; and Jimmy Carter and George H.W. Bush, in 1924.

Now we've had three presidents who were born in calendar year 1946: Bill Clinton (in August), George W. Bush (in July) and Donald Trump (in June). Note that all three were born just a little more than nine months after V-J Day. (For younger readers, that was the end of World War II.)

The U.S. Census Bureau considers 1946 to be the first year of the baby boom, a remarkable and unpredicted sudden surge in births in the United States and numerous other countries. It continued until 1964, which means Barack Obama, who was born in 1961, is also a part of the baby-boom generation.

The leading edge of the baby-boom generation, the oldest members of an enormous age cohort, has made its mark on American life. Growing up in an era of postwar conformity, they insisted on doing their own thing. They listened to and played rock 'n' roll, the first adolescent music genre. They participated in student riots. Their high-school class of 1964 had the highest test scores in history.

Compared with their parents, they attended college more and served in the military less. All seven presidents born between 1908 and 1924 were, in some form, in the military during World War II. Two of the 1946 presidents never were in the military at all, and one served in the Texas Air National Guard.

Two were the sons of men highly successful in quite different fields. One's father was a mysterious figure who died before he was born. But all three graduated from prestigious universities -- Georgetown University and Yale Law School, Yale University and Harvard Business School, and The Wharton School of the University of Pennsylvania.

Of course, each was different. Bill Clinton was a political prodigy, with the capacity to understand public policy and its political implications seemingly off the top of his head. He started his political career early, running the 1972 George McGovern campaign in Texas and almost upsetting a Republican congressman in 1974. In 1976, he was elected Arkansas attorney general, and in 1979, at 32, he became the state's governor.

Clinton had luck, and with his dazzling political skills, he took advantage of it. When his career seemed to be winding down -- he was renominated and re-elected by lackluster margins in 1990 -- he took a chance on running for president against an incumbent who had started the year with 91 percent approval. That guaranteed weak Democratic competition, and Ross Perot's surprise candidacy, which dislodged George H.W. Bush, and surprise (and temporary) withdrawal boosted Clinton.

As president, Clinton had his stumbles and unique disgrace. He was disorganized and undisciplined, but he was also constantly adapting and revising, rewriting State of the Union addresses on his ride to the Capitol. The public mostly approved.

George W. Bush was, in some ways, the opposite. After an unsuccessful House race in 1978, he mostly laid aside politics. After his father lost to Clinton, he seems to have believed that God put him in the way of running for president, and he strove to tutor himself to do the best job possible.

His strength was steadfastness, his weakness (as always, a strength overdone) stubbornness. He was agonizingly slow on midcourse correction, notably on Iraq but also on Social Security reform.

Bush's political strategy, designed to keep Texas from being the next California, worked, but it gave him only small electoral vote majorities. When his job approval dropped, between 2006 and 2008, his party took the worst thumpings it'd had in 25 years.

Donald Trump's strategy followed not George W. Bush's but Ross Perot's. He bet that his trademark stands on trade and immigration (different from every president's since Dwight Eisenhower) -- though costing him votes of college graduates in California, Arizona, Texas and Georgia -- would gain him enough votes from non-college-educated people to win.

The bet paid off. Trump did worse than George W. Bush had done in those states, but it cost him zero electoral votes. Swings by non-college-educated whites in Florida, Pennsylvania, Ohio, Michigan, Wisconsin, Iowa and Maine gave him 100 electoral votes twice won by Barack Obama.

Was that shrewd insight or blind luck? Either way, it perhaps owed something to Perot (born in 1930), who helped make each of these boomers president.